The performance ECU chip is the computer chip in the cars engine which run the car’s data and sends it to the right sector of the engine. Like all computers, it can be upgraded, but it is important to get the right chip to upgrade. The relevant chips here are the erasable kind with a read memory. Incompatibility and computers are notorious. If you get the wrong chip, you could in all actuality, be downgrading your vehicle’s performance instead of upgrading it. Its primary functions are to control the fuel delivery, and if you don’t get the right amount of fuel, your engine can flood or end up stuttering because it’s not getting sufficient flow.
For more info, see The ECU Chip Tuning Guide